Ah interesting you know I am also getting some "ticking" almost like lifter noise. Not sure if this is possibly related to any of your write up or not?

For plugs I think its got AC Delco plugs in it right now? I can't remember exactly and its too cold to go look now. LOL

 

Ugh just got back from the garage and my nephew says both the front and rear O2 sensors are reading the same. So looks like I'm calling the company that sold me this cat back in July and see how I get a replacement.

He thinks it might be because I had a bad thermostat and just replaced it and that it was dumping excess fuel and has fouled up the cat.

 

WOW what an ordeal it is dealing with this company: First they have obviously "outsourced" their call center for returns. Which I don't have a problem with I guess but when the lady is enunciating all the syllables of every word and that pronunciation is being butchered and I can't understand her--then I have a problem.

Secondly they want me to bother my nephew and have him send them an email with his "diagnosis" on why the cat is bad? Yeah "OK" I'm sure he's not busy today and would love to sit down and type up an email and tell you what is wrong with YOUR defective catalytic convertor.

Thirdly they are supposed to be sending an email with the description of what all he needs to include in his "diagnosis" of this bad catalytic convertor. I'm on a Comcast line and I usually get emails extremely fast. I've been waiting over 30 minutes and no email. The guy says "Maybe wait an hour or two and you should get the email". An hour or two? Is this guy serious? I got stuff I need to do this afternoon and wanted to get rolling on this right away.

So in a nutshell if you're looking at purchasing car parts I would NOT recommend they have sub par customer service IMO.

 

Both reading the same? If the front one Bank1 sensor 1 is reading lean for example and the rear is also reading lean that makes sense (for the code you are getting) as explained earlier CAI, fueling.
Now if the front is rich and the rear is also rich then yes the cat is not getting up to temp (therefore below threshold temp) the cat would done.


if you find you do need a cat and decide to get a new one and do not want to re-live the present manufacturer, you can go to www.hottexhaust.com (MAGNAFLOW) and find the cat for your car, proceed to the checkout and enter coupon code gmls4 then update and voila new price to your door... no surprises!

 

OK so if they are reading "lean" it may not be the cat is gone then is that what you are saying? If they are both reading "rich" then that means the cat is gone is that correct?

*EDIT* Just talked to the garage and they said the front is functioning as it should and the back is reading the same as the front one.

 

The p0420 code is probably just because it's not an OEM cat.

The tolerances are very tight, and aftermarket Cats will almost always throw a code. It might not happen right away, but within 3-6 months they usually do.

Most people just get their PCM tuned to remove the P0420 code. That's what I did when I put a high-flow cat on my Monte.

That rear oxygen sensor ONLY reads the cat, doesn't affect anything else. So if the shop can test the cat for you and show that it isn't clogged, then I would probably just try a spark-plug defouler trick (search for it) or get the code tuned out.

 

A properly functioning oxygen sensor oscillates, a O2 sensor that is not up to temp (600*f) does not report correctly. If you were graphing a pre-cat O2 sensor first the engine has to be at operating temp. Then idled for 3-4 min. Then the throttle depressed to wide open position momentarily, the oxygen sensor should change from idle values to between 100mv and 900mv. If the sensor readings don`t change then it could be an air/fuel delivery issue.


Next bring the engine up to 2300-2600 rpm, the voltage on the O2 sensors should change and start to oscillate approx every 1 second. If this happens it is most likely the O2 sensors are working properly. If the signal changes but the voltage is only getting up to 600-700mv or less, the AFR (air fuel ratio) is lean. (Poor fuel delivery, a unmetered air leak, CAI ) or other things. If the voltage oscillates and remains high as in never going below 450mv, then the engine is running rich.


A quick test can determine a lean condition. Un plug a vacuum line downstream of the MAF sensor, this will allow unmetered air into the system producing a lean/leaner condition. Re-connect and allow to idle.


A quick test can determine a rich condition, unplug the fuel pressure regulator vacuum line and plug it, this will cause a rich condition.

 

Well now I'm torn on what to do. This is what I think I'll do:

Get the cat replaced under warranty and then do the "spark-plug defouler trick" so the code doesn't come back.

I figure that will cover me just in case the old cat is bad and will also keep the new one from going bad hopefully or the code from returning.

I hate to tune the PCM and remove the code entirely because what if a legitimate problem arises and I've had that code removed? I just am not comfortable I don't think in doing that.

 

You'll always know when a cat goes bad, either by driveability or the awful smell haha

 

See that's another thing that makes me think the cat is actually not bad. I got plenty of power and no smell and it doesn't glow red or anything.